1. Field of the Invention
The present invention pertains to the art of appliances and, more particularly, to the formation of a washing tub defined by a reinforcing body made from a non-metallic material, such as plastic or fiberglass, and an inner exposed liner formed from a metallic material, such as stainless steel.
2. Discussion of the Prior Art
In appliances which incorporate washing tubs, such as dishwashers and clothes washing machines, it is known to form the tubs in various ways and from numerous different materials. For instance, it is known to make a tub from metal, such as steel, which is coated with a baked-on enamel or porcelain. Such tubs certainly last a long time but can be fairly heavy. A high-end appliance model may incorporate a tub made entirely of stainless steel which does not require any interior coating. In addition to perhaps being a very aesthetically appealing construction, stainless steel tubs may be the most hygienic. Other known tubs are entirely molded of plastic, such as polypropylene. Obviously, forming a tub entirely of plastic is more cost efficient and results in an extremely light weight, yet durable, product.
Unfortunately, there does not exist an appliance tub on the market which is made to exhibit the advantages of many of the known tub constructions. Therefore, there exists a need in the art for an appliance tub, as well as a method of making the same, which is light weight, cost effective and, at the same time, exhibits positive features of a high-end model tub.
The present invention is directed to forming a high-end washing tub in an extremely cost effective and efficient manner. More specifically, the washing tub of the invention includes a light weight, non-metallic reinforcing body and a metallic inner surface liner. In its most preferred form, the invention is directed to a washing tub, such as a clothes washing or dishwashing tub, preferably formed of a relatively thick plastic or fiberglass outer reinforcing body and a thin inner liner layer of stainless steel. With this construction, the materials of the washing tub synergistically combine such that a washing tub exhibiting beneficial characteristics from each of the materials is produced.
In accordance with a first preferred embodiment of the invention, the washing tub is produced through a molding operation typically used in forming a conventional plastic washing tub except, prior to injecting the plastic material into a suitable mold cavity, a core of the mold is spray coated with stainless steel. The air flow rate associated with the spraying machine can be varied during the overall coating process to initially apply a fine-grained layer onto the core and then to follow with a rough and porous layer. With this arrangement, after the mold cavity is formed and the plastic is injected into the mold cavity, the plastic bonds mechanically with the stainless steel.
In another embodiment of the invention, the washing tub is formed with a stainless steel inner surface and a fiberglass reinforcing body. In accordance with this preferred embodiment, the stainless steel material is spray coated onto a core or mandrel and then fiberglass is laid around the stainless steel to create a reinforcing body for the tub. In forming a dishwasher tub, features such as an air inlet and float standpipes could be readily provided for. For instance, in the fiberglass embodiment, standard air inlet and float standpipes could be molded from plastic or made from stainless steel and inserted through the stainless steel liner and retained in place by the fiberglass. Furthermore, a solid piece of stainless steel could be inserted into the core to create a groove for retaining a door gasket.
Additional objects, features and advantages of the washing tub constructed in accordance with the present invention will become more fully apparent below when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.